Sec Form 4 Filing - HUNT RONALD @ Harpoon Therapeutics, Inc. - 2024-03-08

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person HUNT RONALD 2. Issuer Name and Ticker or Trading Symbol Harpoon Therapeutics, Inc. [ HARP] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O NEW LEAF VENTURE PARTNERS, 156 FIFTH AVENUE, SUITE 820 3. Date of Earliest Transaction (MM/DD/YY) 03/08/2024 (Street) NEW YORK, NY10010 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 03/08/2024 A( 1 ) 424 A $ 0 13,224 D Common Stock 03/11/2024 D( 2 ) 13,224 ( 3 ) D ( 2 ) 0 D Common Stock 03/11/2024 D( 2 ) 1,463,386 D ( 2 ) 0 I See Footnote ( 6 ) ( 7 ) Common Stock 03/11/2024 D( 2 ) 395,783 D ( 2 ) 0 I See Footnote ( 8 ) ( 9 ) 8.000% Series A Redeemable Preferred Stock 03/11/2024 D( 2 ) 10,000 D ( 2 ) 0 I See Footnote ( 6 ) ( 7 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Common Stock Warrant (Right to Buy) $ 9.7889 03/11/2024 D( 2 ) 299,430 03/23/2023 03/23/2031 Common Stock 299,430 ( 11 ) 0 I See Footnote ( 6 ) ( 7 ) Common Stock Warrant (Right to Buy) $ 5.8345 03/11/2024 D( 2 ) 686,000 10/25/2023 10/25/2026 Common Stock 686,000 ( 11 ) 0 I See Footnote ( 6 ) ( 7 ) Common Stock Warrant (Right to Buy) $ 5.8345 03/11/2024 D( 2 ) 85,750 10/25/2023 10/25/2026 Common Stock 85,750 ( 11 ) 0 I See Footnote ( 8 ) ( 9 ) Director Stock Option (Right to Buy) $ 21.1453 03/11/2024 D( 2 ) 2,033 ( 12 )( 13 ) ( 12 )( 13 ) Common Stock 2,033 ( 12 ) ( 13 ) 0 D Director Stock Option (Right to Buy) $ 20.1 03/11/2024 D( 2 ) 1,016 ( 12 )( 13 ) ( 12 )( 13 ) Common Stock 1,016 ( 12 ) ( 13 ) 0 D Director Stock Option (Right to Buy) $ 20.1 03/11/2024 D( 2 ) 3,214 ( 12 )( 13 ) ( 12 )( 13 ) Common Stock 3,214 ( 12 ) ( 13 ) 0 D Director Stock Option (Right to Buy) $ 6.657 03/11/2024 D( 2 ) 2,300 ( 12 )( 13 ) ( 12 )( 13 ) Common Stock 2,300 ( 12 ) ( 13 ) 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other HUNT RONALD C/O NEW LEAF VENTURE PARTNERS 156 FIFTH AVENUE, SUITE 820 NEW YORK, NY10010 X X Signatures /s/ Frank J. Lanza, Attorney-in-Fact 03/11/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents shares of the Issuer's common stock, par value $0.0001 per share ("Common Stock") issuable upon the settlement of restricted stock units ("RSUs"). Each RSU represents a contingent right to receive one share of Common Stock. The fully vested RSUs were granted to the Reporting Person pursuant to the Issuer's Non-Employee Director Compensation Policy in lieu of prorated retainer fees totaling $9,753.00 for the first quarter of 2024. ( 2 )This Form 4 reports securities disposed of pursuant to the terms of the Agreement and Plan of Merger (the "Merger Agreement"), dated as of January 7, 2024, by and among the Issuer, Merck Sharp & Dohme LLC, a New Jersey limited liability company ("Parent"), and Hawaii Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Parent ("Merger Sub"), pursuant to which Merger Sub merged with and into the Issuer on March 11, 2024, with the Issuer surviving the merger as a wholly owned subsidiary of Parent (the "Merger"). ( 3 )Includes 13,224 RSUs which are subject to rounding as a result of the 1:10 reverse stock split effective September 1, 2023. ( 4 )Pursuant to the terms of the Merger Agreement, at the effective time of the Merger (the "Effective Time"), each outstanding RSU was cancelled and automatically converted into the right to receive an amount in cash (without interest and subject to any applicable withholding or other taxes) equal to the product of (i) the Common Stock Merger Consideration (as defined below) payable with respect to such RSU multiplied by (ii) the total number of shares of Common Stock subject to such RSU immediately prior to the Effective Time, with the number of shares of Company Common Stock subject to any such Company RSU that vests based on the achievement of performance goals determined in accordance with the applicable award agreement. ( 5 )Pursuant to the terms of the Merger Agreement, at the Effective Time, each outstanding share of Common Stock was cancelled and automatically converted into the right to receive $23.00 in cash, without interest (the "Common Stock Merger Consideration"). ( 6 )These shares are held directly by New Leaf Biopharma Opportunities II, L.P. ("BPO-II"). The sole general partner of BPO-II is New Leaf BPO Associates II, L.P. ("NLBA-II"). The sole general partner of NLBA-II is New Leaf BPO Management II, L.L.C. ("BPO Management-II"). Each of NLBA-II and BPO Management-II disclaim beneficial ownership of these securities and this report shall not be deemed an admission that NLBA-II or BPO Management-II are beneficial owners of such securities for purposes of Section 16 or any other purpose, except to the extent of their respective pecuniary interests therein. ( 7 )The Reporting Person, a board member of the Issuer, and Vijay K. Lathi (collectively, the "BPO-II Managing Directors") are managing directors of BPO Management-II and may each be deemed to have shared voting and investment power with respect to these securities. Each of the BPO-II Managing Directors disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein. ( 8 )These shares are held directly by New Leaf Ventures III, L.P. ("NLV-III"). The sole general partner of NLV-III is New Leaf Venture Associates III, L.P. ("NLVA-III"). The sole general partner of NLVA-III is New Leaf Venture Management III, L.L.C. ("Management-III"). Each of NLVA-III and Management-III disclaim beneficial ownership of these securities and this report shall not be deemed an admission that NLVA-III or Management-III are beneficial owners of such securities for purposes of Section 16 or any other purpose, except to the extent of their respective pecuniary interests therein. ( 9 )The Reporting Person, a board member of the Issuer, and Vijay K. Lathi (collectively, the "NLV-III Managers") are managing directors of Management-III and may be deemed to have shared voting and investment power with respect to these securities. Each of the NLV-III Managers disclaims beneficial ownership of these securities and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein. ( 10 )Pursuant to the terms of the Merger Agreement, at the Effective Time, each share of the Issuer's Series A Redeemable Preferred Stock, par value of $0.0001 per share ("Series A Preferred Stock") issued and outstanding was cancelled and the holder thereof was entitled to receive 3,577.77 per share of Series A Preferred Stock in respect of each Series A Preferred Stock determined in accordance with the terms of the Series A Preferred Stock, subject to applicable withholding taxes. ( 11 )Pursuant to the terms of the Merger Agreement, at the Effective Time, by virtue of the Merger and without any further action on the part of the holders thereof or the parties to the Merger Agreement, each warrant that was outstanding and unexercised immediately prior to the Effective Time, in accordance with its terms, ceased to represent a warrant exercisable for Common Stock and became a warrant exercisable for the Common Stock Merger Consideration that such holder would have been entitled to receive if such warrant had been exercised immediately prior to the Effective Time. ( 12 )Pursuant to the terms of the Merger Agreement, immediately prior to the Effective Time, each outstanding option to purchase shares of Common Stock granted under an Issuer equity plan (each, a "Stock Option"), to the extent unvested, became fully vested and exercisable effective immediately prior to, and contingent upon, the Effective Time. Pursuant to the terms of the Merger Agreement, at the Effective Time, ( 13 )(continued from footnote 12) (i) each Stock Option that was outstanding and unexercised immediately prior to the Effective Time and that had a per share exercise price that is less than the Common Stock Merger Consideration (each, an "In the Money Option") was cancelled in exchange for the right to receive an amount in cash (without interest and subject to any applicable withholding or other taxes) equal to the product of (1) the total number of shares of Common Stock subject to such Stock Option immediately prior to the Effective Time and (2) the excess of the Common Stock Merger Consideration over the per share exercise price payable for such Stock Option immediately prior to the Effective Time and (ii) each Stock Option other than an In the Money Option then outstanding and unexercised was cancelled with no consideration payable in respect thereof.

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